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sched/core: Fix preempt warning in ttwu 

John reported a DEBUG_PREEMPT warning caused by commit:

  aacedf26fb ("sched/core: Optimize try_to_wake_up() for local wakeups")

I overlooked that ttwu_stat() requires preemption disabled.

Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: aacedf26fb ("sched/core: Optimize try_to_wake_up() for local wakeups")
Link: https://lkml.kernel.org/r/20190710105736.GK3402@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2019-07-10 12:57:36 +02:00 committed by Ingo Molnar
parent f632a8170a
commit e3d85487fb
1 changed files with 3 additions and 1 deletions
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4
kernel/sched/core.c
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@ -2399,6 +2399,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
unsigned long flags;
int cpu, success = 0;
preempt_disable();
if (p == current) {
/*
* We're waking current, this means 'p->on_rq' and 'task_cpu(p)
@ -2412,7 +2413,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
* it disabling IRQs (this allows not taking ->pi_lock).
*/
if (!(p->state & state))
return false;
goto out;
success = 1;
cpu = task_cpu(p);
@ -2526,6 +2527,7 @@ unlock:
out:
if (success)
ttwu_stat(p, cpu, wake_flags);
preempt_enable();
return success;
}